1. Field of the Invention
The invention relates to a device for assisting with driving an automotive vehicle. The invention also relates to a method for assisting with driving an automotive vehicle.
2. Description of the Related Art
The present invention relates to methods and devices that are intended to provide assistance with driving automotive vehicles, when exterior luminosity is low and requires lights to be turned on, but also when exterior luminosity is high.
When exterior luminosity is low, it is known to use light beams to illuminate the road scene. The light beams emitted by the illuminating devices with which vehicles are equipped are regulated by international regulations that set maximum and minimum allowable intensities, for example on a screen placed away from and on the axis of the illuminating device. These regulations have the aim of ensuring simultaneously that:                the illuminating device of the vehicle equipped therewith satisfactorily illuminates the road scene toward which the driver is driving, so that he is able to apprehend his environment under the best possible conditions, and that        the drivers of other vehicles are not dazzled, whether they are driving in the opposite direction (oncoming vehicles) or in the same direction (vehicles in front).        
With the aim of meeting these regulatory aims and with a view to improving the comfort and safety of the driver, a plurality of solutions have been proposed. One thereof consists in using a device for assisting with driving composed of a pulsed illumination source synchronized with a variable transmission screen, in such a way that the illumination reaches its maximum value when the transmission coefficient of the variable transmission screen reaches its maximum value, i.e. a maximum transparency, and in such a way that the illumination reaches its minimum value when the transmission coefficient of the variable transmission screen reaches its minimum value, i.e. a minimum transparency.
Thus, by virtue of this synchronization, the driver benefits completely from his lights, while decreasing the risk of being dazzled by exterior light sources, because the vision of the driver is greatly restricted when the transparency of the variable transmission screen is at its minimum.
Furthermore, the pulsed illumination does not dazzle the drivers of other vehicles since they perceive only an average illumination that is set to meet the aforementioned regulations.
Nevertheless, one disadvantage of this solution is that it makes it more difficult for the driver to see the luminosity of any exterior light source that is not however responsible for dazzle, such as public lighting, the lights of other vehicles located sufficiently far away to not be dazzling, traffic lights, etc. In particular for the lights of other vehicles, such a solution may lead to the loss of or at the very least limit the perception of speed or path that these lights enable, when they are not turned off.
In addition, using a pulsed illumination source requires more electrical power to be delivered, for the same average illumination, than is required with an unpulsed illumination source because of the decrease in the efficiency of the light sources when they are pulsed with higher currents (in the current state of the art).
Likewise, when luminosity is high, it is possible for glare effects to be encountered, which it would be desirable to treat.